1. Field of the Invention
The invention relates to a system for sorting objects from among a mixture of objects of a limited number of kinds. More particularly, it relates to a sorting system in which the objects are presented for inspection and classification in a limited number of possible orientations. Such a system may be used for sorting components into specific orientation for further processing or for automatic assembly into larger units.
2. Description of the Prior Art
In some cases, the orientation of components can be maintained from a previous process, the components being loaded into a magazine. But processes such as deburring, plating or even bulk storage may lead to randomly orientated components. Mechanical systems exist for orientated feeding, such as known vibratory bowl feeders or rotating drums. However the output tracks and component deflection devices of such systems have to be specially designed for each component.
To avoid special track and deflector design a vision-based system may be used to view the components and to make a sorting decision based on a computer processing of the image provided by such a vision system. Such a system is described in the article "A practical vision system for use with bowl feeders", Proceedings of the First International Conference on Assembly Automation, A. J. Cronshaw et al, pages 265-274, Brighton, England, March 1980. In this system, the component is moved transversely relative to a linear array of photodetectors which are scanned repetitively to provide a binarized picture of the component. In use, the system is shown good components and the binarized picture is displayed to a programmer with knowledge of the component. Using a light pen, specific features are selected for incorporation in a set of templates which are subsequently used for testing further components of unknown quality. It is a disadvantage that a skilled programmer is required. It is an object of the invention to provide an object sorting system in which it is only necessary to present examples of desired and unwanted objects to the system in a learning mode, after which sorting can be carried out, without the operator having any knowledge of the object features.